Bangladesh police has arrested three Rohingya men and a Bangladeshi who were trying to smuggle 800,000 methamphetamine pills into the country from Myanmar, an official said. The arrests come as Bangladesh struggles to deal with a massive influx of Rohingya Muslims fleeing unrest in neighbouring Myanmar’s Rakhine state.

Officers from Bangladesh’s elite Rapid Action Battalion (RAB) detained the four men on Wednesday on a fishing trawler in the estuary of the Naf river, which divides the two countries. “We caught four people trafficking Yaba tablets. Three of them are Rohingya from Myanmar and the other one is a Bangladeshi,” Major Ruhul Amin, an RAB area commander, told AFP. “They were carrying 800,000 yaba tablets on a boat. They brought the yabas from Myanmar. Two of the Rohingyas came here recently. And the other one is an old refugee,” he added. Yaba, a Thai word meaning “crazy medicine”, is a concoction of methamphetamine and caffeine that has become popular among young people in Bangladesh.

Some 480,000 Rohingya Muslims have fled violence in Rakhine since August 25 and taken refuge in Bangladesh’s southeastern district of Cox’s Bazar. The influx began when deadly attacks by Rohingya militants on Myanmar police posts prompted a huge crackdown by the military. In recent years Bangladeshi security forces have seized millions of yaba tablets from traffickers attempting to enter Cox’s Bazar by land and sea.

Last week two Rohingya men were arrested from a boat in the Naf river by Bangladesh border guards with some 430,000 yaba pills. Last year a Bangladesh counter-narcotics official told AFP the country was struggling to shut down trafficking from Myanmar, in part because it is difficult to patrol the vast Naf river. He said yaba pills were being produced in bathroom-sized labs in border areas in Myanmar.